长期施肥下红壤磷素积累的环境风险分析

ENVIRONMENTAL RISK ANALYSIS OF ACCUMULATED PHOSPHORUS IN RED SOIL UNDER LONG-TERM FERTILIZATION

以长期(始于1988年)施肥的旱地红壤为材料,研究了土壤磷积累与磷吸附的关系,通过分析土壤磷素吸附特征参数及面向环境的土壤磷素表征值的变化,讨论了长期施肥下旱地红壤磷素积累的环境风险。结果表明:长期施磷可显著增加红壤磷素的累积量,降低土壤对外源磷的固持能力,提高土壤的有效磷及易解吸磷的量。供试的7个试验处理,除NK处理及花生秸秆本田还田处理外,土壤有效磷均高于20mg kg-1,已达到丰磷状态,但只有配施厩肥处理的土壤磷素存在环境风险。因此,应在兼顾土壤磷素的农业效应和环境安全的前提下,建立新的施肥制度,使磷素资源的利用更加合理化。

Relationship between soil phosphorus（P） accumulation and characteristics of P adsorption in red soil under long-term（20 years） fertilization were explored,and environmental risk of P accumulation P in the soil was discussed through analyzing changes in P adsorption eigenvalue and environment oriented soil P token value.Results show that long-term P fertilization markedly increased P accumulation and the contents of available P and readily desorbable P in the soil,but decreased the soil adsorption capacity of foreign P.In all the seven treatments in the experiment,except Treatment NK and Treatment PSI（peanut stem incorporation）,the amounts of Olsen-P in the soil were all over 20 mg kg-1,reaching a P level of abundance,but only in Treatment PM（pig manure） did P accumulation pose some environmental risk.Consequently a new fertilization system should be worked out by taking into account both the agricultural effects and environment safety of soil P,to further rationalize the use of P resources.